"It was the result of decades of abuse and controlling and intimidating behaviour. He was a tyrant who wouldn’t let his family live outside of his domination.

"Our father was a terrorist living within our own home; he had no cause but to frighten his family and to generate his own esteem from trampling and bullying us. For over a decade we had tried to leave on numerous occasions but he manipulated and threatened on every occasion."

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Lance Hart who murdered his wife Claire and daughter Charlotte at a leisure centre in Spalding on July 19 2016. Credit: SWNS/SWNS

Hart shot his wife and daughternear the Castle Sports Complex in Spalding, Lincolnshire, last July after she had left him and ended their marriage days earlier.

As his daughter lay dying, her last words were: "It was my dad who shot me."

Mr Hart said he and his brother had been working abroad and had saved up enough money to help his mother and sister escape from him and start a new life.

"We moved mum out of our house whilst our father was out, only a few days before the event on the 19th July," he said.

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Charlotte Hart, 19, who was murdered by her father Lance Hart.Credit: SWNS/SWNS

"Killing our mother and sister was our father’s final denial of the future we had spent our lives trying to create for mum and Charlotte, the life that they deserved. He killed himself in an act of cowardice, finally showing how little he had to live for outside of punishing his family for his own distorted sense of power."

Mr Hart took the step of speaking out to pay tribute to the support he has received from his younger brother Ryan, 26, in the hope their story will help other families.

"I wouldn’t be here without my little brother," he added.

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Charlotte Hart, 19 who was killed at Castle Leisure centre, Spalding on the July 19 2016. Credit: SWNS/SWNS

"I act strong, but he is strong. Even when we struggled through our darkest moments against our father, Ryan dared to remain resistant when I had broken down and couldn’t face any more.

"He was still able to love and believe in a world that our father had filled with hate

Ryan protected us; he never hid but always threw himself in the firing line to protect us.

"For everything our father has done to attempt to destroy Ryan, he has failed. Ryan is the strongest, most kind hearted person and refuses to let the hate triumph over the love he fought for. My little brother is my hero and I love him.

"I hope that our story can encourage others to stand up to and speak out about the many forms of domestic abuse. I hope it empowers those who are suffering its consequences to take action."

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Charlotte Hart, 19 who was killed at Castle Leisure centre, Spalding on the July 19 2016.Credit: SWNS/SWNS

Last year Coroner Paul Cooper concluded the deaths of Charlotte and Claire were unlawful killings and Mr Hart's was suicide, adding: "He knew exactly what he was going to do.

"In my view, this was a cold, calculated, scheming man who went out and deliberately murdered his wife and daughter."

Hart's suicide note described how he ate a "last supper" of his favourite meal before he carried out the killings.

"I have just had my favourite meal, paella, and I'm sitting in the sun with a glass of red wine," it read.

Last year Ryan and Luke said: "Charlotte and our mum were our inspiration and purpose in life.

"They were the two most virtuous and beautiful people we have ever encountered. It is not possible to describe how unfairly and how cruelly they have been taken from us.

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Charlotte Hart and her mother Claire who were murdered by Lance Hart.Credit: SWNS/SWNS

"Our world is a darker place because they have gone."

Mrs Hart, who had previously battled cancer and been diagnosed with Multiple Sclerosis, told colleague Dale Pateman that her husband was a controlling and selfish man saying she had "become worn out by his behaviour".

Her daughter Charlotte, a student, had moved in with her.

Charlotte had dropped out of a midwifery course but was due to start a teacher training course at Northampton University before her death.